Forum Moderators: open
window.onbeforeprint - Fires just prior to the page being printed
window.onafterprint - Fires immediately after the page to be printed out has been loaded into printer queue/cache.
It can also be actioned inside the BODY (can it be linked to other elements?):
<body onbeforeprint="dothis()">
I have not tried this myself, but I gather it is IE5+ only.